The Mars rover robots Spirit and Opportunity are equipped with a panoramic camera called the Pancam that was developed at Cornell University. The rovers have sent back hundreds of Pancam images with new ones showing up all the time. According to a Cornell news story, the Pancam lead scientist, Jim Bell, has collected many of the most visually impressive Pancam Mars images and created a book called Postcard from Mars. Samples images and more details about the book's contents can be found on the Postcards from Mars website. More Pancam images can be found in the Pancam image gallery or the JPL Spirit and Opportunity Panorama archive.